1. Field of the Invention
The present invention relates to a ceramic package with a lid for radiating and eliminating unwanted heat generated from a chip-type device during an operation of the device, and more particularly to a ceramic package with a lid covering the ceramic package, which is provided at its upper surface with radiating grooves or pins to allow heat generated from the chip-type device to be efficiently radiated to the outside.
2. Description of the Prior Art
In general, a chip-type device mounted on a product is sure to generate heat during its operation. Since such heat gives birth to noise or malfunction of the device, various structures for radiating heat are in demand.
In particular, in order to manufacture simple and light mobile phones, surface acoustic wave filters (referred to as “SAW filters” hereinafter) and surface acoustic wave duplexers (referred to as “SAW duplexers” hereinafter) have become more and more miniaturized. With the popularization of such compact SAW duplexers, SAW duplexers having the dimensions of 5.0 mm×5.0 mm are extensively used, which are smaller than the dimensions of 9.5 mm×7.5 mm, and products having the dimensions of 3.8 mm×3.8 mm are in the process of being developed.
In accordance with miniaturization of products, packages are also being miniaturized. Due to the miniaturization of packages, there is a problem in heat radiation of chip-type devices such as SAW filters.
As shown in FIG. 1, an SAW duplexer 102 which is one such chip-type device, is surface-mounted on a package substrate 100, which is prepared by a plurality of laminated substrates with a cavity 112 therein. The package substrate 100 on which the SAW duplexer 102 is mounted is provided at its bottom with via holes 110. The via holes 110 are filled with electrode material to transfer heat. Furthermore, the package substrate 100 is provided over the cavity with a lid 106, which is attached to the top surface of the package substrate 100 by a brazing process. The substrate on which the SAW duplexer 102 is mounted includes a phase control circuit 108 therein.
In the manufacture of the package substrate, since the electrodes 110 are embedded in the bottom of the package substrate on which the SAW duplexer 102 is mounted, roughness is caused by deterioration of the bottom surface, thereby causing difficulty in mounting of the SAW duplexer 100. In addition, because of the uneveness of the bottom surface, the upper surface of the SAW duplexer 102 is not level at the time of wire bonding process, thereby increasing the failure rate of wire bonding. If the via holes 110 filled with the electrodes are pressed at the time of the laminating procedure, the electrode surfaces are expanded, causing deformation of the ceramic green sheet. This results in a camber phenomenon of the package.
In a conventional ceramic package shown in FIG. 2, it is necessary to control the impedance of a receiver 130 to be infinitely great so as not to permit signals outputted from a transmitter 120 from being inputted to the receiver 130 rather than a antenna 140. To this end, the phase control circuit 108 must be provided between the antenna 140 and the receiver 130. However, since the phase control circuit 108 must be formed in a substrate to be separated from the via holes 110, there is a limitation in its design.